Marking systems that transport paper or other media are well known in the art. These marking systems include electrostatic marking systems, non-electrostatic marking systems, printers or any other marking system where paper or other flexible media or receiving sheets are transported internally to a an output device such as a finisher and compiler. Many machines are used for collecting or gathering printed sheets so that they may be formed into books, pamphlets, forms, sales literature, instruction books and manuals and the like.
The finisher and compiler are located at a site in these marking systems after the receiving sheets (paper) have been marked. A finisher is generally defined as an output device that has various post printer functions or options such as hole punching, corner stapling, edge stapling, sheet and set stacking, letter or tri-folding, Z-Folding, Bi-folding, signature booklet making, set binding [including thermal, tape and perfect binding], trimming, post process sheet insertion, saddle stitching and others.
The compiler often employs a compiling wall or tray where frictional drive elements hereinafter paddle wheels with elastomeric blades or “paddle wheels” (PW) are used to drive sheets (paper) against the compiling wall for registration of the staple or bind edge of a set. The force of these frictional drive elements on the sheet is critical and, must be controlled within narrow limits. In the case of Deflection Loaded technologies such as Paddle Wheels, the compiler element drive force has been found to be dependent on the type of wheel used and the type of elastomeric blades on the paddle wheel.
The compiling capacity and bind edge sheet registration can be compromised with moderate to severe curl on the sheets if improper wheels and blades are used. The curl can be concave up or concave down and curl build-up generally progressively increases as the paper stack height grows. Excessive curling caused by poor blade performance can cause poor set registration and possibly paper jams or sheet damage.
As discussed above in [003] finisher compiling systems often employ frictional drive elements such as elastomeric paddle wheels to drive the individual sheets square (deskewed) and against the registration edge. With such compliant drive elements, the normal force on the paper and, thus, the drive force and noise generated thereby will increase as the paper builds up in the compiler tray. As the distance between the shaft and the top of the paper stack decreases, the deflection of the rubber blades increases and with it the noise and drive forces that are transmitted to the top sheet of the stack. As the paddle blade contacts the paper, a significant audible noise is produced as blade-paper contact occurs. A solution to this excessive audible noise produced by existing print art paddles is needed for the HVF to meet specified noise allowance for the product(s).
A rapid increase in on-demand service to provide large-volume small-scale printing of brochures etc. by use of color/black and white multifunction machines has been exhibited. Even ordinary offices are stepping up their efforts at in-house production of conference paper, simple booklets, manuals and other materials by establishing service departments for intensively processing prints in large quantities. Noise levels in these type systems have become very important since the office space is relatively small and noise can be magnified. Such customers require relatively quiet post-processing functions such as high-speed/high-precision punching, stapling and paper folding work with simultaneous print output and realization of high-speed/high-quality print output with a high degree of reliability.
“Drive elements or frictional drive elements” as used in this disclosure and claims include any suitable paddle wheel and blade used. Also, in the present embodiments, any number of paddle wheels and any suitable number of rubber paddle wheel blades may be used. The size, type and number of paddle wheels and blades, for best results, depend upon many variations in the paper used such as size of paper, weight of paper, coated or non-coated paper, paper for color prints, paper for monochrome prints, etc and the specific compiler tray geometry. Also, curl suppressors can be desirably used together with the paddle wheels to improve paper registration. The desired or ideal drive force and generated noise of the blades in the paddle wheels will, of course, vary as the conditions, paper and paper size and other variables change or exist; the ideal drive force and noise levels produced can be easily established and acted on through simple tests.